The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. below what value are approximately 97.5% of the students?
a. $215
b. $195
c. $255
d. $275
e. $295

Option D) $275

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = $235

Standard Deviation, σ = $20

We are given that the distribution of amount of money spent by students is a bell shaped distribution that is a normal distribution.

Formula:

We have to find the value of x such that the probability is 0.975

Calculation the value from standard normal z table, we have,  

Approximately 97.5% of the students spent below $275 on textbook.

solution:

as, mean is defined as sum of all the observations divided by total number of observations.

and , median is mid value of the data whether arranged in ascending order or descending order.

consider, roadsters:

2,3,4,5,6,7,8,9

mean =

also, median= , because number of observations is even, so median is mean of two mid values.

now, coming to bandits

2,3,4,5,6

mean =  

median = 4, as number of observations is odd.

so, roadsters has greater median as well mean than bandits.

→option a is true about the repairs performed on 2 types of cars:

bandits have lower median and mean than roadsters.

d

step-by-step explanation:

i used the pitagoras theoreme